As is well known, environmental diseases have been increased as air and soil has been polluted, and the concern for a well-being and health has been increased. Accordingly, rhinitis' patients washing their noses with normal saline in the market have been increased.
Hypochlorous acid (HOCl) is well known as effective and harmless chemicals to people as well as chemicals for disinfecting various viruses. However, Journal of Burns and Wounds, a medical journal published on Apr. 11, 2007, showed in its article titled “Hypochlorous Acid as a Potential Wound Care Agent” that HOCl has never been used as medical supplies for curing viral infection.
On the other hand, normal saline is achieved by four chemical mechanisms as follows.Cl2+H2OHOCl+H++Cl−  Chemical equation 1Cl2+H2OHOCl+H++Cl−  Chemical equation 2aCl2+H2OHOCl+H++Cl−  Chemical equation 2bOCl−+H+HOCl  Chemical equation 3
That is, HOCl can be generated by hydrolyzing chlorine gas in accordance with the chemical equation 1, or by electrolyzing saline solution in accordance with the chemical equation 2a and 2b, or by oxidizing hypo-chlorite in accordance with the chemical equation 3. In the case of chemical equation 1, however, it is troublesome and risky to handle chlorine gas which is sometimes in the form of poisonous gas. Also, with regard to the chemical equations 2a and 2b, it is written in the above article that it is very difficult to realize the targeted concentration of HOCl by electrolysis. Therefore, the above journal shows that it is most desirable to generate HOCl for medical uses through using commercially available hypo-chlorite in accordance with the chemical equation 3.
On the other hand, it is written at 71 page of the above journal that the minimum bactericidal concentrations (MBC) of HOCl enough to disinfect viruses at normal temperature are shown as follows.
TABLE 1GermsMBC (ppm)Escherichia coli0.7Pseudomonas aeruginosa0.35Staphylococcus aureus0.173Staphylococcus epidermidis0.338Micrococcus luteus2.77Corynebacterium amycolatum0.169Haemophilus influenzae0.338Proteus mirabilis0.340Staphylococcus hominis1.4Staphylococcus haemolyticus0.338Staphylococcus saprophyticus0.35Candida albicans2.7Klebsiella pneumoniae1.7Serratia marcescens0.169Sterptococcus pyogenes0.169Enterobacter aerogenes0.676Candida albicans0.17Methicillin-resistent Staphylococcus aureus0.682Vancomycin-resistent Enterococcus faecium2.73
From the above table 1, even very low concentration of HOCl can sterilize most of germs effectively. However, a solution with unlimitedly higher concentration of HOCl would not be used for medical uses. Therefore, the above journal describes that the unreliable amount of HOCl generated by an electrolysis cannot be used for medically curing any infection such as by directly injecting or spraying it into a human body. Specifically, when the concentration of HOCl exceeds over 6 ppm, it causes trouble on sensitive parts of human body such as a mucosa of a nose and eyes, further it causes the stench of the solution, and thus, a solution with over 6 ppm concentration of HOCl has been regarded as not being used for medical treatment. In this regard, the document published on January in 1994 by the U.S. Environmental Protection Agency has also announced that a desirable concentration of the free chlorine (in other words, it is referred as ‘residual chlorine’) for an adult with weight of 70 Kgf is recommended as less than 6 ppm.
Therefore, it is most important to manufacture sterilized normal saline with maintaining the precise low concentration of free chlorine including HOCl in order for applying HOCl to a medical treatment. Also, maximizing the ratio of HOCl in the free chlorine is needed for better sterilizing effect.
On the other hand, HOCl has a relatively long half-life time of 44 hour in the inside of a human body. However, in the water, as shown in FIG. 16, the half-life time of HOCl falls to 3 minutes, and thus, the effective sterilizing efficacy of HOCl cannot be expected after the half-life time is passed.
Considering above, HOCl has been widely admitted for its possible use for medical treatments because HOCl has a sterilizing efficacy against diverse germs. However, as HOCl has very short half-life time outside of human body, and as HOCl has not been realistically manufactured with being controlled within the predetermined lower range of concentration, it has been regarded as impossible to apply HOCl to patients for medical purpose such as treating diseases infected by diverse germs.
Accordingly, there has been great need for method of manufacturing HOCl with the predetermined constant lower range of concentration enough to terminate germs as well as not to cause the disgusted feeling to patents so that the free chlorine especially including HOCl can be realistically applied to patents for medical purpose.